Method of manufacturing a cushion inner spring

ABSTRACT

An inner spring consisting of a sheet of flexible material, a multiplicity of slots in the sheet, and a coiled wire secured to the sheet by each individual coil being positioned through a corresponding one of the slots; and the method of its manufacture.

United States Patent 1191 Richardson et al.

1451 Apr. 23, 1974 METHOD OF MANUFACTURING A CUSHION INNER SPRING Inventors: Delmar John Richardson; Louis Marton; Harley Davis Maddaford, all of Winnipeg, Manitoba, Canada Assignee: Richardson Manufacturing Ltd.,

' Winnipeg, Manitoba, Canada Filed: Feb. 16,1972

Appl. No.: 226,825

Foreign Application Priority Data June 3, 1971 US. Cl.., 264/249, 29/432, 29/434, 29/505, 206/80 .R, 264/242, 267/84, 267/ 142 Int. Cl. B29c 19/00 Field of Search 29/428,432, 434, 505; V I 26 7/84/14 Z; 206/80 R;-264/249, 242

Canada 1 14746 3,079,672 Bain et al 29/432 UX Primary Examiner-Charlie TfMoo n Attorney, Agent, or Firm-Lawrence I. Field [5 7] ABSTRACT An inner springconsisting of a sheet of flexible material, a multiplicity of slots in the sheet, and a coiled wire secured to the sheet by each individual coil being positioned through a corresponding one of the slots; and the method of its manufacture.

2 Claims, 5 rawing Figures METHOD OF MANUFACTURING A CUSHION INNER SPRING FIELD OF INVENTION This invention relates to a cushion inner spring construction and a method of making the same. The inner spring is especially suitable for use in a cushion in which air is permitted to circulate through the cushion for ventilating purposes.

DESCRIPTION OF PRIOR ART Various types of ventilated cushions are known, these types having a coil or coiled wire arranged in rows, a spiral configuration or a star configuration. The coil or coiled wire is held in place in the cushions usually by wires or by interlocking of crossing coils. Alternatively, pockets may be sewn through the cushion to position the coiled wire.

The easiest configuration to manufacture and prov vide adequate support in a cushion appears to be that using a single coiled wire placed in the form of a spiral, and the two following patents show two methodsof securing such a coiled wire in a cushion.

US. Pat. No. 2,129,353 which issued to E. P. Harley on Sept. 6th, 1938, discloses a cushion wherein a spiral pocket is formed between the two sides of a cushion by stitching in a spiral manner, and the coiled wireis positioned in the pocket. It will be appreciated that Harleys cushion is difficult to manufacture as it is necessary to position the coiled wire in a spiral form and then sew through the cushion to form the pockets after the coiled wire in place. The holding of the coiled wire during stitching involvesan awkward manufacturing step and the quality of the finished product will suffer due to this manufacturing problem. Harleys cushion also uses lossely woven mesh sides which cannot be satisfactorilystitched and furthermore will not stay stitched in a satisfactory manner due to the stitching covering the major portion of the cushion which encounters the most bending during use.

U.S. Pat. No. 3,146,030 which issued to S. L. Dennison et al on Aug 25th, 1964, discloses a spirally positioned coiled wire in a seat cushion, the coiled wire being held in place by a relatively stiff wire which is wound in a spiral form and upon which the coiled wire is threaded. Again it will be appreciated that this cushion is awkward to manufacture, and the finished product will be relatively rigid especially near its outer region due to the existence of the relatively rigid wire which holds the coiled wire in position.

SUMMARY OF INVENTION In an attempt to overcome the problems associated with the prior art cushions, the cushion inner spring of this invention utilizes a flexible sheet through which are formed slots or slits in a spiral locus, the slots being inclined to the locus at an angle approximately equal to the pitch of a coil of the coiled wire which is to be used as the supporting member. The coiled wire is secured to the flexible sheet by the individual coils penetrating respective slots. The flexible sheet together with the mounted coiled wire is then sewn between the two sides of a cushion in a well known manner, binding around the periphery if required for strengthening purposes. A peripheral frame consisting of a length of wire the shape of the 'cushion can be inserted inside the cushion and around the spiral coiled wire form to assist in holding the cushion in shape.

It will also be appreciated that, without departing from the scope of this invention, the slots can be arranged in a different pattern to a spiral locus so that a different arrangement of the coiled wire can be achieved.

To manufacture the cushion inner spring construction of this invention a sheet of flexible material the size of the required cushion is formed with slots in a suitable configuration such as angled to a spiral locus. A coiled wire is then secured to the flexible sheet by placing each individual coil through its respective slot. The slots can be cut through the flexible sheet or can be formed by positioning the coiled Wire in a desired configuration, placing the flexible sheet on the coiled wire, and heating the coiled wire a sufficient amount to melt slots throughthe flexible sheet and permit the sheet todrop into place with the individual coils penetrating the slots. The heating of the coiled wire can be conveniently done electrically by including the coiled wire in an electrical circuit.

It will be'noted that the cushion inner spring of this invention is relatively easy to manufacture and the quality of the product is maintained throughout use due to the secure positioning of the coiled wire.

BRIEF DESCRIPTION OF DRAWINGS The invention will not be described with reference to the accompanying drawings in which preferred embodiments are detailed.

In' the drawings,

FIG. 1 is a plan view of the inner spring of this invention shown in place in a cushion withthe top cover partly removed.

FIG. 2 is an enlarged plan view of part of the structure of FIG. 1.

FIG. 3 is a side elevational view on 3-3 of FIG. 2.

FIG. 4 is an enlarged view of part of another embodiment of flexible sheet for positioning the coiled wire.

DESCRIPTION OF PREFERRED EMBODIMENTS Referring to FIGS. 1 through 4, the inner spring consists of a flexible sheet 1, such as a plastic sheet, and a coiled wire 3. The sheet 1 is provided with slots in the form of slits 5 which are cut at an angle to a spiral locus having an outer end 7 and an inner end 9. The angle of the slits 5 to the locus is approximately equal to the pitch angle of the coiled wire 3. Each convolution of the coiled wire 3 is placed through a corresponding one of the slits 5 and the coiled wire 3 is thereby held in position. The inner end of the coiled wire 3 at the end 9 of the locus can be secured to the next turn of the coiled wire 3 if required to prevent this end of the coiled wire from twisting out of the plane of the sheet 1. Ventilation holes 11 are formed at various positions throughout the sheet 1 for extra ventilation purposes. A frame such as a wire frame 13 is positioned around the coil 3 and inside the outer periphery of the cushion 15 to hold the cushion in shape. Alternatively, the wire 13 may be dispensed with to simplify manufacture and to provide a more flexible cushion.

The sheet. 1 is secured by stitching 17 to the sides of the cushion, a reinforcing strip 21 preferably being utilized.

' Referring to FIG. 5, instead of slits 5, slots in the form of elongated apertures 19 can be cut in the sheet 1 for holding the coiled wire 3 in place. An inner spring using this type of sheet is easier to assemble than the sheet having slits and also permits more ventilation through the cushion.

The method of manufacturing the inner spring of this invention is to form slots in a flexible sheet and hold a coiled wire in a set configuration by inserting the individual coils through respective slots. The slots are formed in the flexible sheet by either cutting or attaching electrical leads to the inner and outer ends of the coiled wire 3, placing the sheet 1 over the coiled wire 3, passing an electric current through the coiled wire 3 until it is heated to a degree sufficient to melt the sheet 1 where contact occurs between the coiled wire and the sheet, ceasing the electric current flow, and permitting the sheet to drop into place with the individual coils penetrating the formed slots.

We claim: 7 v

l. A method of manufacturing a cushion inner spring consisting of forming slots in a sheet of flexible material and securing a coiled wire to the sheet by placing individual coils through respective slots, by positioning the coiled wire in the required configuration, placing the sheet upon heating the coiled wire, the coiledwire to a temperature sufficient to melt the sheet at its points of contact with the coiled wire, terminating the heating, and permitting the sheet to drop freely into place with the individual coils positioned through the formed slots. y

2. The method of claim 1 wherein the coiled wire is heated by passing an electrical current through it. 

1. A method of manufacturing a cushion inner spring consisting of forming slots in a sheet of flexible material and securing a coiled wire to the sheet by placing individual coils through respective slots, by positioning the coiled wire in the required configuration, placing the sheet upon heating the coiled wire, the coiled wire to a temperature sufficient to melt the sheet at its points of contact with the coiled wire, terminating the heating, and permitting the sheet to drop freely into place with the individual coils positioned through the formed slots.
 2. The method of claim 1, wherein the coiled wire is heated by passing an electrical current through it. 